Generally, a door glass run provided to a door of an automobile is used to shut off outside air so as to prevent noise, foreign material such as dust, etc. contained in the outside air from flowing into the automobile.
Referring to FIG. 1, there is shown a perspective view illustrating an automobile; and FIG. 2 is a cross-sectional view taken along the line II--II of FIG. 1, illustrating construction of a door glass run according to the related art. A door glass run 10 is maintained in a state to be fitted into a channel frame disposed between a door's outer panel and a door's inner panel to be securely fastened thereto, and is made from rubber to have a desired elasticity. The door glass run 10 includes a body 12, and the body 12 is formed with a closed space 14 and a door glass receiving space 16. An elastic lip portion 18 is arranged between the closed space 14 and the door glass receiving space 16. The elastic lip portion 18 is capable of being elastically deformed and functions as a partition wall which separates the closed space 14 and the door glass receiving space 16 from each other. The closed space 14 has a closed cross section. The door glass receiving space 16 is positioned adjacent to the closed space 14 and includes a portion which is opened to the outside. On edges of the body 12, which define the door glass receiving space 16, a first close-contact lip 20 and a second close-contact lip 22 are formed such that they are opposed to each other. An opening 24 is defined between the first close-contact lip 20 and the second close-contact lip 22. A door glass 26 can be received into the door glass receiving space 16 through the opening 24.
Referring now to FIG. 3, there is shown a cross-sectional view illustrating the door glass 26 and the door glass run 10 which are properly engaged with each other. When the door glass 26 is fully closed, the door glass 26 is inserted into the door glass receiving space 16 through the opening 24 while elastically deforming the first close-contact lip 20. By this, the first close-contact lip 20 is closely contacted to one surface of the door glass 26 while being rotated in a counterclockwise direction due to its elastic force. Then, an end surface of the door glass 26 which continuously moves upward in the door glass receiving space 16 elastically deforms the elastic lip portion 18. By this, the second close-contact lip 22 is closely contacted to the other surface of the door glass 26 while being rotated in a clockwise direction. Accordingly, by the fact that the elastic lip portion 18 is closely contacted to the end surface of the door glass 26 and the first and second close-contact lips 20 and 22 are closely contacted to inner and outer surfaces of the door glass 26, outside air is prevented from flowing into an automobile.
However, since the door glass run 10 of the related art, constructed as mentioned above, is made from rubber, the property of rubber is changed with the lapse of time and the door glass run 10 is hardened. By this, an original configuration of the door glass run 10 is changed irrespectively of whether the door glass run 10 is engaged with the door glass 26 or not. Therefore, as shown in FIG. 4, the door glass 26 is improperly engaged with the door glass run 10, and the first and second close-contact lips 20 and 22 of the door glass run 10 are squeezed by the door glass 26, and thereby the first and second close-contact lips 20 and 22 cannot be properly engaged with the inner and outer surfaces of the door glass 26. Accordingly, it is impossible to perfectly shut off the outside air whereby noise and foreign material such as dust, etc. can flow into the automobile through a gap between the close-contact lips 20 and 22 and the door glass 26 so as to deteriorate a comfortable feeling by occupants. The above-mentioned problems can be more serious when there is play in the door glass 26 due to its operation. Further, as the door glass run 10 is repeatedly squeezed by the door glass 26, durability of the door glass run 10 can be shortened.